AT2R基因转染对血管平滑肌细胞增殖核抗原表达的影响

目的:探讨血管紧张素Ⅱ2型受体(AT2R)基因体外及体内转染对血管平滑肌细胞(VSMC)增殖核抗原(PCNA)表达的影响。方法:细胞爬片及大鼠颈动脉球囊损伤后,局部转染带有绿色荧光蛋白报告基因的AT2R重组腺病毒载体(pAd-AT2R)或病毒载体(pAd-GFP),于细胞转染后48h及术后14d取材,应用免疫组织化学染色、免疫荧光双标染色和激光共聚焦技术检测了VSMC及血管中AT2R与PCNA的表达关系。结果:pAd-AT2R转染VSMC后,在激光共聚焦显微镜下胞质及胞核有绿色荧光蛋白表达;同时在胞质有红色荧光AT2R表达,胞核无蓝色荧光,PCNA表达阴性,无红色荧光AT2R表达的VSMC胞核有蓝色荧光,PCNA表达阳性。pAd-AT2R在体转染大鼠颈动脉后,新生内膜及中膜中PCNA阳性表达率显著低于未转染组和pAd-GFP组[(27.29±5.81)%∶(72.25±4.47)%,(68.43±9.12)%,P<0.01];在激光共聚焦显微镜下,绿色荧光及红色荧光AT2R主要分布于新生内膜、中膜、外膜,内膜散在蓝色荧光PCNA表达,在红、绿色荧光处无蓝色荧光,PCNA表达阴性,无红、绿色荧光处,有蓝色荧光,PCNA表达阳性。结论:AT2R基因体外及体内转染可抑制VSMCPCNA表达,ATR基因转染能抑制新生内膜增生。     

反义血管紧张素Ⅱ受体Ⅰ_B基因转移对大鼠颈动脉损伤后新生内膜的影响

目的　探讨腺病毒载体介导的大鼠反义血管紧张素Ⅱ受体ⅠB(AT1B)RNA转移对大鼠颈动脉损伤后新生内膜的影响。方法　利用重组腺病毒载体将大鼠反义AT1B RNA转移至大鼠颈动脉球囊损伤模型中 ,2 1天后观察其对新生内膜形成的影响。结果　用腺病毒载体转导大鼠反义AT1BRNA至大鼠球囊损伤的颈动脉 ,与对照组相比 ,2 1天后损伤血管新生内膜 /中层面积比降低了 4 7%(P <0 0 0 1)。结论　反义AT1BRNA对血管成形术后再狭窄可能有一定的预防作用。     

间充质干细胞移植实现AT2R基因在体可调控表达在再狭窄形成的作用及机制

目的研究间充质干细胞(mesenchymal stem cells,MSCs)细胞移植实现AT2R基因在体可调控表达在大鼠颈动脉损伤后新生内膜形成中的作用及机制。方法采用常规分子生物学方法连续两个回合转染体外培养的MSCs,获得受到强力霉素(Dox)调控的低背景、高诱导表达AT2R基因的双重稳定MSCs系;建立大鼠颈动脉球囊损伤动物模型,将双重稳定MSCs系种植于动脉损伤局部,通过尾静脉注射强力霉素,分别于术后14天、28天行病理切片,采用免疫组化法及RT-PCR等技术检测AT2R基因在新生内膜中的表达及其对新生内膜形成(intima/media ratio,I/M)及纤维连接蛋白(FN)的影响。结果成功建立低背景、高诱导表达AT2R基因的双重稳定MSCs系。该MSCs系受到Dox给予/去除的紧密调控,诱导后48h就可使AT2R明显表达,在Dox干预72h后AT2R表达进一步增强;这种表达的可诱导性至少在8周内维持稳定。免疫组织化学及RT-PCR检测显示:球囊损伤大鼠血管后14天及28天,Dox组新生内膜中AT2R的表达显著高于对照组、MSC组、MSC转染组(mRNAF=335.746;蛋白F=51.277,P0.01),而其内膜/中膜面积比(I/M)较其他各手术组显著降低(F=72.417,P0.01)。同时Dox组新生内膜层及中膜层中FN阳性染色较对照组、MSC组和MSC转染组显著减弱。结论血管损伤局部导入双重稳定MSCs系后AT2R表达受到Dox的良好调控,可有效抑制球囊损伤后大鼠颈动脉新生内膜增生。同时Dox诱导AT2R表达后,新生内膜中FN表达减少,可能是MSCs细胞移植实现AT2R基因在体可调控表达有效抑制新生内膜增生的机制之一。     

Fas配体基因导入对大鼠颈动脉损伤后新生内膜的影响

目的 :探讨腺病毒载体介导 Fas配体 （Fas L）基因导入对大鼠颈动脉损伤后新生内膜的影响。方法 :利用重组腺病毒载体将 Fas L 导入大鼠颈动脉球囊损伤的内膜 ,14d后观察其对新生内膜形成的影响。结果 :通过腺病毒载体介导导入 Fas L 基因的被球囊损伤的大鼠颈动脉 ,与 Ad- β gal基因的对照组相比较 ,14d后损伤血管新生内膜 /中膜面积比降低了 73%（P<0 .0 1）。结论 :Fas L 可抑制新生内膜的增生。     

腺病毒介导BTEB2基因转染对动脉损伤后新生内膜增生的影响

目的 :构建反义转录元件结合蛋白 2 (BTEB2 )重组腺病毒载体并研究BTEB2反义RNA对动脉损伤后新生内膜增生的影响。方法 :通过聚合酶链反应 (RT PCR)法从培养的大鼠血管平滑肌细胞中制备BTEB2cDNA ,将其反向克隆至腺病毒载体 ,构建反义BTEB2重组腺病毒 ;用重组腺病毒局部转染球囊损伤的大鼠颈动脉 ,观察反义BTEB2基因转染对BTEB2蛋白表达及损伤动脉新生内膜形成的影响。结果 :构建的BTEB2反义重组腺病毒经鉴定正确 ,其滴度为 5× 10 9/ml;反义BTEB2重组腺病毒转染可明显抑制BTEB2蛋白表达及新生内膜增生。结论 :成功构建了反义BTEB2重组腺病毒载体 ;BTEB2反义RNA可明显抑制大鼠颈动脉球囊损伤后的新生内膜增生。     

过表达p27基因抑制血管损伤后新生内膜的形成

目的　探讨p2 7基因转染对血管损伤后新生内膜形成的影响。方法　以腺病毒为载体转染p2 7基因 ,用MTT法观察其对血管平滑肌细胞增殖的影响 ,用流式细胞仪检测细胞周期 ;在兔颈总动脉球囊损伤模型上转染p2 7基因 ,采用免疫组织化学法检测p2 7基因的表达 ,检测其对新生内膜形成的影响。结果　p2 7可明显抑制培养的血管平滑肌细胞增殖 ,细胞停滞于G1期。兔颈总动脉球囊损伤后转染p2 7基因可以减少新生内膜的形成达 2 7 4 3%。结论　以腺病毒为载体转染p2 7基因可以有效地抑制血管平滑肌细胞增殖及血管损伤后新生内膜的形成。     

腺病毒介导高血压相关基因转移对兔颈动脉球囊损伤后新生内膜形成的抑制作用

目的 探讨腺病毒载体介导的新基因高血压相关基因(Hypertension-related gene,HRG-1)转移对兔颈总动脉球囊损伤后新生内膜形成的影响。方法 兔颈总动脉球囊损伤后,经血管腔内转染含有HRG-1的腺病毒载体(AdHRG-1)或含有绿色荧光蛋白报告基因的空载腺病毒载体(AdGFP),以生理盐水处理为对照。于术后3、7和28 d取材,分别进行外源基因表达检测、PCNA染色和定量组织形态学分析。结果 应用逆转录-聚合酶链反应和免疫组织化学方法分别证实了基因转移后3 d HRG-1在兔颈动脉壁内的表达;PCNA免疫组织化学染色显示,转染AdHRG-1后7 d兔颈动脉内膜和中膜PCNA阳性细胞指数较转染AdGFP组明显降低[(21.4±2.5)％对(45.6±3.8)％,(6.4±1.1)％对(17.8±1.9)％,P<0.05]。基因转移后28 d血管壁定量组织形态学分析显示,转染AdHRG-1组血管新生内膜面积及内膜面积与中膜面积比均显著低于转染AdGFP组[(0.13±0.03)mm2对(0.45±0.14)mm2,0.19±0.02对0.70±0.15,P<0.01],血管腔面积则显著增加[(0.88±0.07)mm2对(0.57±0.27)mm2,P<0.01],而转染AdGFP组与生理盐水处理组间无显著性差异。结论 以腺病毒为载体经血管腔内转染HRG-1可有效抑制球囊损伤后血管平滑肌细胞增殖和新生内膜形成。     

血管紧张素Ⅱ2型受体介导抑制大鼠颈动脉新生内膜增生的机制

目的:探讨血管紧张素Ⅱ2型受体(AT2R)介导抑制新生内膜增生作用的机制。方法:大鼠颈动脉球囊损伤后,局部转染带有大鼠AT2R基因重组腺病毒转染(pAdCMV／AT2R)或空载腺病毒转染 (pAd-GFP),分正常组(6只)、未转染组(18只)、pad-GFP组(18只)、pAdCMV／AT2R组(18只)。于术后7、14、21天取材,用逆转录一多聚酶链反应、Western印迹杂交检测AngⅡ1型受体(AT1R)、AT2R、胞外调控激酶1和2、基本转录元件结合蛋白2在大鼠颈动脉壁中的表达变化。结果:未转染组和pad-GFP组AT1R、AT2R、胞外调控激酶1和2、基本转录元件结合蛋白2的7、14、21天mRNA及蛋白表达显著高于正常组,pAdCMV／AT2R组AT2R的表达显著高于正常组、未转染组和pAd-GFP组(P<0．01),胞外调控激酶1和2、基本转录元件结合蛋白2的表达显著低于未转染组和pAd-GFP组(P<0．01),而AT1R的表达在未转染组、pAd-GFP组、pAdCMV／AT2R组无显著差异(P>0．05)。结论:AT2R灭活AT1R激活的胞外调控激酶1和2,降低基本转录元件结合蛋白2表达,可能是AT2R介导抑制新生内膜形成的机制之一。     

AT2R基因在体可调控表达对大鼠血管损伤后MMP-2表达的影响

目的研究间充质干细胞（MSCs）移植实现血管紧张素Ⅱ2型受体（AT2R）基因在体可调控表达对大鼠颈动脉损伤后新生内膜中基质金属蛋白酶2（MMP-2）表达的影响。方法采用常规分子生物学方法连续两个回合转染体外培养的MSCs，获得受到强力霉素（Dox）调控的低背景、高诱导表达AT2R基因的双重稳定MSCs系；建立大鼠颈动脉球囊损伤动物模型，将双重稳定MSCs系种植于动脉损伤局部，通过尾静脉注射Dox，分别于术后14、28d行病理切片，采用免疫印迹、免疫组化法及RT-PCR等技术检测AT2R基因在新生内膜中的表达及其对MMP．2表达的影响。结果成功建立了低背景、高诱导表达AT2R基因的双重稳定MSCs系。该MSCs系受到Dox给予／去除的紧密调控，诱导后48h即可使AT2R显著表达，在Dox干预72h后AT2R表达进一步增强；这种表达的可诱导性至少在8周内维持稳定。免疫印迹、免疫组化及RT-PCR检测显示：球囊损伤大鼠血管后14d及28d，Dox组新生内膜中AT2R的表达显著高于对照组、MSC组、MSC转染组（P〈0．01）；同时，Dox组新生内膜中MMP．2阳性染色较对照组、MSC组和MSC转染组显著减弱（P〈0．01）。结论血管损伤局部导人双重稳定MSCs系后AT2R表达受到Dox的良好调控。Dox诱导AT2R表达后，新生内膜中MMP-2表达减少，可能是MSCs细胞移植实现AT2R基因在体可调控表达有效抑制新生内膜增生的机制之一。     

慢病毒载体在大鼠颈动脉球囊损伤模型中的应用及观察

目的:研究携带绿色荧光蛋白(Green fluorescent protein,GFP)的慢病毒转染球囊损伤大鼠颈动脉的效率和可行性,为利用慢病毒载体介导的基因治疗预防血管再狭窄奠定基础。方法:将携带GFP的慢病毒载体(pGC-LV-GFP载体)和慢病毒包装质粒供转染293T细胞,完成慢病毒颗粒包装及滴度测定。包装产生的慢病毒Lenti-GFP转染至球囊损伤的大鼠颈动脉。术后28d,损伤及病毒转染血管段标本分别行荧光显微镜、光镜检查,评估慢病毒的转染效率及内膜增生情况,并与假手术组(Sham组)、PBS对照组进行比较。结果:经包装产生的Lenti-GFP滴度为2×109TU/mL;术后28d,Sham组与PBS组血管中膜弹力层仅见微弱的自发性绿色荧光,而Lenti-GFP组动脉壁全层可见较强的绿色荧光分布;PBS组与Lenti-GFP转染组大鼠损伤的颈动脉均可见明显内膜增生,内膜和中膜面积之比差异无统计学意义。结论:Lenti-GFP成功转染至球囊损伤的大鼠颈动脉,并能维持目的基因稳定长期的表达,是血管再狭窄基因治疗的理想载体。     

Inhibitory action of rat insulin and synthetic rat C-peptide on insulin secretion in the perfused rat pancreas

Summary In order to determine whether both insulin and C-peptide have an inhibitory action on insulin secretion, the isolated rat pancreas was perfused with exogenous rat insulin or synthetic rat C-peptide in the presence of high or low concentration of glucose. In the presence of 2.8 mM glucose, exogenous rat insulin (4 or 10 ng/ml) and C-peptide 1 and 2 (100 ng/ml) show no effect on the insulin levels in the outflow from the perfused pancreas. However, the insulin response to 16.7 mM glucose decreased in the presence of exogenous rat insulin or synthetic rat C-peptide, showing a biphasic pattern of glucose-induced insulin release. When rat insulin or C-peptide were added at 20 min and removed at 40 min while the isolated pancreas was exposed to a 60-min glucose infusion (16.7 mM), glucose-induced insulin secretion decreased during the infusion of rat insulin or C-peptide. The present study clearly showed that exogenous rat insulin and synthetic rat C-peptide 1 and 2 inhibited glucose-induced insulin secretion. Although the suppressive mechanisms of the exogenous insulin and the C-peptide on insulin release are not yet proved, the inhibitory process is considered to be related to cyclic AMP in the pancreatic B-cell.     

Sequence homology between RNAs encoding rat alpha-fetoprotein and rat serum albumin

We have determined the sequences of the recombinant DNA inserts of three bacterial plasmid cDNA clones containing most of the rat alpha a-fetoprotein mRNA. The resultant nucleotide sequence of alpha-fetoprotein was exhaustively compared to the nucleotide sequence of the mRNA encoding rat serum albumin. These two mRNAs have extensive homology (50%) throughout and the same intron locations. The amino acid sequence of rat alpha-fetoprotein has been deduced from the nucleotide sequence, and its comparison to rat serum albumin's amino acid sequence reveals a 34% homology. The regularly spaced positions of the cysteines found in serum albumin are conserved in rat alpha-fetoprotein, indicating that these two proteins may have a similar secondary folding structure. These homologies indicate that alpha-fetoprotein and serum albumin were derived by duplication of a common ancestral gene and constitute a gene family.     

The spontaneously diabetic Wistar rat (the “BB” rat)

Summary A longitudinal study of 51 weanlings from 5 litters of BB Wistar rats was undertaken to characterize the time course of the spontaneous diabetic syndrome. Nine rats developed overt diabetes. An abnormal glucose tolerance preceded the onset of the syndrome in 6 of these 9 rats. No other clinical or metabolic variable measured was predictive of the development of this syndrome. In these rats, the onset was remarkably abrupt, followed by rapid clinical deterioration with marked hyperglycaemia, glycosuria, ketonaemia and hypoinsulinaemia attained within 2 to 8 days. Pronounced insulitis was present in the early stages of the syndrome, resulting in complete B-cell destruction at the time of sacrifice at 7 to 40 days. Among the 42 littermates, 9 revealed sequential abnormalities in oral glucose tolerance tests performed at weekly intervals (to age 90–120 d) though remaining aglycosuric and maintaining normal fasting plasma glucose levels. In 7 of these rats, a milder form of the same islet inflammatory lesion seen in the overtly diabetic animals was present. Thus the new features identified are: 1) a time course of evolution from normoglycaemia to overt diabetes telescoped into a period of days, and 2) a chemical stage or form with an insulitis similar to that found in the early stages of overt diabetes.     

Binding and cross-linking of iodinated rat prolactin to rat hepatic prolactin receptor

Basal parameters for binding and cross-linking of 125I-rat prolactin (rPRL) to lactogenic (PRL) binding species present in crude membrane fraction (CMF) or detergent-solubilized preparations of rat liver have been investigated. (1) The highest specific binding to CMF was obtained with an incubation time of 50 h at 20 degrees C and with a 50 mM potassium phosphate buffer adjusted to pH 8.5. (2) Cross-linking of 125I-rPRL to binding sites in CMF with disuccinimidyl suberate (DSS) showed the autoradiographic appearance of an Mr 40,000 binding species. (3) No specific binding or cross-linking of rPRL was seen in Triton X-100-solubilized CMF. This is probably due to Triton X-100-induced changes in the physical properties of rPRL. (4) Specific binding of 125I-rPRL was detected in CHAPS-solubilized CMF. Following cross-linking the autoradiographic appearance of a binding species with an Mr value of 40,000 was shown. 125I-hGH was cross-linked to three PRL binding species with Mr 82,000, 40,000 and 35,000 in CHAPS-solubilized preparations. (5) In Golgi-enriched low-density membrane preparation 125I-rPRL was cross-linked to Mr 82,000, 40,000 and 35,000 species. It is proposed that the inability of rPRL to be cross-linked to Mr 82,000 and 35,000 species present in CHAPS-solubilized preparation is the result of CHAPS-induced changes of rPRL binding properties and low solubilizing capacity of CHAPS. (6) In conclusion, this study shows that also the iodinated endogenous hormone, rat prolactin, and not only hGH identifies high and low molecular forms of the rat liver prolactin receptor.     

Sudanophilia of rat lymphocytes

Summary A significant proportion of large lymphocytes in laboratory rats is stained with Sudan black B. The increase in the counts of sudanophilic blood lymphocytes over control values indicated reliablely the recovery of lymphocytic function even when total lymphocyte, small or large lymphocyte counts were normal or reduced.